Ellipse compass

ABSTRACT

An ellipse compass is provided that has a base plate, a top plate, an intermediate plate, and rotatable disc therebetween with pins adjustable as to their positions engaged in the top plate and intermediate plate such that relative motion is obtained therebetween to permit drawing of ellipses, and which may include a gauge to determine the setting of the minor axis dependent on the size of the major axis.

United States Patent 1 [111 3,724,080

Kane Apr. 3, 1973 [54] ELLIPSE COMPASS Primary Examiner-Alarry N. l-laroian [75] Inventor: Leslie Kane, Philadelphia, Pa. Attorneywzachary wobensmlth 2nd [731 Assignee: Kane and Sullivan, Inc., Mechanic- [57] ABSTRACT svlue An ellipse compass is provided that has a base plate, a [22] Filed: May 3, 1972 top plate, an intermediate plate, and rotatable disc [21] Appl. No.: 249,875 therebetween with pins adjustable as to their positions engaged in the top plate and intermediate plate such that relative motion is obtained therebetween to per- [52] US. Cl. ..33/30 D mit drawing of ellipses, and which may include a [51] Int. Cl. ..B43l 11/04 gauge to determine the setting of the minor axis de- [58] Field of Search ..33/3O R, 30 D, 30 G, 31 pendent on the size of the major axis.

[56] References Cited UNITED STATES PATENTS 9 Claims, 4 Drawing Figures 296,100 4/1884 Abbott ..33/30 D I L R a9 4 4f- ,Hti 'fil7 2/"/ I a 5 PATENTEDAPR 3 I973 SHEEI 2 [1F 2 ELLIPSE COMPASS BACKGROUND OF THE INVENTION readily adjusted to obtain ellipses of varying sizes has long been desired. Most of the equipment available requires complicated mechanism that compromises the characteristics of the ellipse as drawn.

One such structure is disclosed in the U.S. Pat. to Rabinowitz, No. 2,477,203 which shows an ellipsograph including upper and lower discs with a downwardly projecting pin on the lower disc and an upwardly projecting pin on the upper disc, with the pins being adjustable to vary the minor and major axes of the ellipse. The discs are connected by a toothed gear arrangement so that they rotate together at the same speed when one of them is rotated and in the same direction.

The US. Pat. to Kirk et al., No. 1,168,081 shows an ellipsograph wherein a pencil is secured to a slidable arm carried on a carriage that is mounted to a plate. Movement of a crank arm causes the slidable arm to be moved transversely across the plate in a circular direction while the carriage is moved longitudinally across the plate. Rotation of the crank arm causes the end of the arm with which it is engaged to move in a circular direction fixed by an arm that is pivotally connected thereto and to the side of the slidable arm.

The US. Pat. to Sundman, No. 918,218, shows an ellipsograph which has a circular base frame with an open center portion. A T shaped member made up of chord bars connected together is provided which carries a pencil or scriber and is pivotedlyattached to the frame at 90 degree intervals by pivot mechanisms. The pivot mechanisms each include an arm with an adjustable sliding cuff mounting thereon and to the chord bars so that rotation provides an ellipse type figure.

All of the structures are complicated in construction, difficult to use and the results obtained are less than satisfactory. The structure of my invention is simple to manufacture and use and provides for drawing of ellipses that are quite acceptable to critical draftsmen.

SUMMARY OF THE INVENTION An ellipse compass is provided that includes a base plate, and two movable plates above the base plate with a rotatable disc therebetween and in engagement so that rotation of the disc causes relative motion of the topmost plate causing a scriber or pencil held in a portion thereof to move in an elliptical path, and which base plate includes a gauge bar determining the minor axis dependent onthe major axis.

The principal object of the invention is to provide an ellipse compass that can be readily adjusted to provide difierent sizes of ellipses.

A further object of the invention is to provide an ellipse compass that provides for the drawing of an accurate ellipse.

A further object of the invention is to provide an ellipse compass that is simple to construct, is durable and has a long service life.

A further object of the invention is to provide an ellipse compass that has a gauge for determining the size of the minor axis for a predetermined major axis.

A further object of the invention is to provide an ellipse compass that is easy to service.

Other objects and advantageous features of the invention will be apparent from the description and claims.

DESCRIPTION OF THE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawings forming part thereof, in which:

FIG. 1 is a perspective view of the ellipse compass of the invention;

FIG. 2 is an enlarged side elevational view of the compass of FIG. 1;

FIG. 3 is an exploded perspective view of the ellipse compass of FIG. 1, and

FIG. 4 is a vertical sectional view, enlarged, taken approximately on the line 4-4 of FIG. 1.

It should, of course, be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings the ellipse compass 10 includes a base plate 1 1 of rectangular shape. The plate 11 has a front edge 12, a rear edge 14, and side edges 15 and 16. The plate 11 can be constructed of any preferred light weight material such as aluminum or synthetic plastic.

A depressed portion 17 is provided in plate 1 1 beginning at a line 18 to the left of side edge 16 and terminating at a line 20. The portion 17 is formed by removing part of plate 11 for a depth of one half the thickness of plate 11 and extends from front edge 12 to rear edge 14, and from line 18 to line 20.

A circular opening 21 is provided centrally located in the portion 17 and provides access for observation from the bottom 22 of plate 1 l.

The portion 17 has a lower plate 25 slidably carried therein which plate 25 is of rectangular configuration. A notch 23 in the edge 16 provides access for adjustment as explained below.

The shape of plate 25 is defined by a straight rear edge 26, with a pair of opposite side edges 27 extending perpendicularly forwardly therefrom and terminating at corner points 28.

From the points 28 edges 29 extend angularly inwardly to points 30 where edges 31 are connected thereto and extend angularly outwardly to points 32 to provide edge notches. Edges 33 extend angularly inwardly from points 32 to points 34. Edges 35 extend inwardly perpendicular to edges 27 to points 36.

Edges 37 extend convergingly inwardly and forwardly from points 36 and meet at locator point 40 which is on the longitudinal centerline of lower plate 25.

The plate 25 is provided with a transverse forward slot 41 adjacent and between points 32, and a transverse rear slot 42 adjacent rear edge 26.

A disc '45 is provided above plate 25 with a peripheral groove 46 therearound with four rollers 47 engaged in groove 46.

The rollers 47 have integral spacers 48 which locates disc above the plate 25 and are rotatably retained to plate 1 1 by four machine screws 50 engaged in holes 51 in plate 1 1.

The disc 45 has a flat top surface 52 and a flat bottom surface 53. A minor axis pin assembly 55 is provided on the bottom surface 53 of disc 45 which includes a block 56 affixed to the disc 45 adjacent its outer edge 57 and a block 58 to the left of the central axis of the disc 45 as seen in FIG. 2. The blocks 56 and 58 have a threaded rod 59 rotatably carried therein which rod 59 has a minor axis adjustment wheel 60 affixed thereto. The rod 59 carries a bottom pin block 61 which has a pin 62 extending downwardly therefrom and is normally engaged in slot 42 in plate 25. The pin block 61 can be positioned at any desired location along the rod 59 by rotation of the wheel 60,appropriate indicia (not shown) for the diameter of the major axis can be provided on the surface 53 under the rod 56.

The disc 45 on the top surface 52 has a major axis pin assembly 65 thereon which includes a block 66 mounted adjacent the outer edge 57 and a block 67 to the right of the center axis of the disc 45 as seen in FIG. 3. The blocks 66 and 67 have a threaded rod 68 rotatably carried thereby which rod 68 has a major axis adjustment wheel 69 affixed thereto.

The wheel 69 extends into a depression 70 in the disc 45.

The rod 68 carries an upper pin block 71, and is free to move therealong upon rotation of the wheel 69. The pin block'7 1 has a pin 72 extending vertically upwardly therefrom which is normally engaged in a transverse slot 73 in top plate 75.

lndicia 74 can be provided on the top of plate 75 along slot 73 and of a scale to determine the size of ellipse desired.

The top plate 75 has a rectangular portion 76 with side edges 77 and 78, rear edge 79, and front edges and 81. The rear edge 79 and the front'edges 80 and 81 are retained from other than longitudinal movement by four spacer rollers 85 which locate the plate 75 above the disc 45 and which are retained in place by the screws 50.

The plate 75 between the two front edges 80 and 81 has a rectangular tongue portion 86 extending perpendicularly forwardly which tongue has a flat portion 87, a downwardly extending bent portion 88, and flat forwardly extending fingers 89. The fingers 89 have a slot 90 therebetween and a pencil or scriber holder assembly 91 thereon movable forwardly and rearwardly in the slot 90. i

The pencil holder 91 includes an outer sleeve 92, with a central bore 93, and an exterior flange 94. A coil spring 95 is carried in bore 93, with a stepped washer 96 above spring 95 and a coil spring 97 above washer 96 and bearing thereagainst in the assembled condition.

A tapered two piece split plug 98 bears against the spring 97 and has a bore 99 therein for the reception of a pencil 100. The plug 98 has a sleeve 101 in enclosing relation thereto with a tapered inner bore 102 which retains the plug 98 and causes the pieces of the plug to be forced together to grip and guide the pencil 100.

A cam ring 103 is provided above the sleeve 101 which ring has a central bore 104 to receive the pencil 100.

A leaf spring 105 is secured to sleeve 92 and bears on the upper surface 106 of the cam ring 103 forcing the cam ring 103 and plug 96 downwardly.

A pencil clamping screw 107 extends in a hole 108 in cam ring 103 in communication with bore 104 and engages and holds the pencil 100 at a set position.

A device for determining the correct setting of the minor axis which setting is dependent on the major axis is provided adjacent to plate 11 and includes stationary locating plate 110 connected to plate 11 by a flexible hinge 111.

The device operates on the principle that the minor diameter of a set degree of a set major diameter is determined by the equation:

Major diameter X (SINE) Minor diameter X (DEGREE) The plate 110 has a wheel 112 rotatably secured thereto by a pin 114 and has two openings 115 and 116 therein which respectively permit viewing of the (SINE) and the (DEGREE) as formed on an appropriate scale (not shown) on the wheel 112.

The bottom surface 120 of the plate 110 can be coated with a suitable gripping adhesive material that will retain the plate 110 on the material on which the ellipse is to be drawn while the operator manipulates the apparatus. 2

The mode of operation will now be pointed out.

A pencil 100 is placed in the bores 104, 102 and retained by the screw 107 with cam ring 103 being positioned to provide the desired downward pressure on the pencil 100.

The major axis diameter being known the major axis pin assembly 65 is adjusted as desired with the pin 72 in slot 73. The wheel 112 is set to the corresponding sine displayed in opening 115 and the minor diameter is determined by the reading from opening 116. The pin- 62 in slot 42 is adjusted to the indicated location.

The relative adjustments of the pins 72 and 62 can be made by repeated trials if desired without resort to the setting indicated at openings 1 15 and 1 16.

The locator point 40, the edges 37,- and points 32 are placed in position on the material on which the ellipse is to be drawn and the pencil 100 is moved forward.

The pencil moves transversely in slot 41 in plate 25 and longitudinally in slot 90 in plate 75. The plate 25 moves forwardly and rearwardly in the direction of the major axis of the ellipse and the disc 45- is caused to rotate which causes the plate 75 to move in the direction of the minor axis, the relative movements of the plates 25 and 75 determining therefore the size of the ellipse as fixed by the major and minor axis settings.

The operation can be repeated as desired or adjusted to provide different sizes of ellipses.

I claim:

l An ellipse compass which comprises a base plate,

a lower plate mounted on said base plate for movement transverse to one axis of said base plate,

said lower plate having a slot perpendicular to its direction of movement,

a disc mounted above said lower plate and rotatably supported by said base, a first axis pin assembly carried by said disc and having a pin engaged in the slot in said lower plate,

' an upper plate above said disc carried by said base plate for movement parallel to the direction of said one axis, said upper plate having a slot perpendicular to its direction of movement, r a second axis pin assembly carried by said disc and having a pin engaged in the slot in said upper plate, and an ellipse scriber member,

mounting members for said scriber member on one of said plates for slidable movement with respect to said one of said plates in a slot perpendicular to the direction of movement of said plate and in engagement in a slot in the other of said plates perpendicular to the direction of movement of said other plate, the composite movement of said plates as controlled by the setting of said pins effecting a controlled elliptical movement of sald scriber member. 2. An ellipse compass as defined in claim 1 in which said axis pin assemblies include adjusting members for said pins for determining the lengths of major and minor ellipse axes.

3. An ellipse compass as defined in claim 1 in which said base plate has a plurality of rollers engaging the periphery of said disc in supporting relation thereto.

4. An ellipse compass as defined in claim 1 in which said upper plate has a plurality of rollers engaging opposite edges thereof for guiding and supporting said upper plate.

5. An ellipse compass as defined in claim 3 in which said upper plate has a plurality of rollers engaging opposite edges thereof for guiding andsupporting said upper plate,

said plate engaging rollers and said disc engaging rollers having common axes.

6. An ellipse compass as defined in claim 2 in which said base plate has an opening for access to one of said axis pin assemblies.

7. An ellipse compass as defined in claim 1 in which said scriber member includes a pencil and pencil holder.

8. An ellipse compass as defined in claim 1 in which said mounting members include a tongue portion on said upper plate with a slot therealong along which said scriber member is movable.

9. An ellipse compass as defined in claim 1 in which setting indicating members are carried by said base plate for indicating the respective length settings of the major and minor ellipse axes. 

1. An ellipse compass which comprises a base plate, a lower plate mounted on said base plate for movement transverse to one axis of said base plate, said lower plate having a slot perpendicular to its direction of movement, a disc mounted above said lower plate and rotatably supported by said base, a first axis pin assembly carried by said disc and having a pin engaged in the slot in said lower plate, an upper plate above said disc carried by said base plate for movement parallel to the direction of said one axis, said upper plate having a slot perpendicular to its direction of movement, a second axis pin assembly carried by said disc and having a pin engaged in the slot in said upper plate, and an ellipse scriber member, mounting members for said scriber member on one of said plates for slidable movement with respect to said one of said plates in a slot perpendicular to the direction of movement of said plate and in engagement in a slot in the other of said plates perpendicular to the direction of movement of said other plate, the composite movement of said plates as controlled by the setting of said pins effecting a controlled elliptical movement of saId scriber member.
 2. An ellipse compass as defined in claim 1 in which said axis pin assemblies include adjusting members for said pins for determining the lengths of major and minor ellipse axes.
 3. An ellipse compass as defined in claim 1 in which said base plate has a plurality of rollers engaging the periphery of said disc in supporting relation thereto.
 4. An ellipse compass as defined in claim 1 in which said upper plate has a plurality of rollers engaging opposite edges thereof for guiding and supporting said upper plate.
 5. An ellipse compass as defined in claim 3 in which said upper plate has a plurality of rollers engaging opposite edges thereof for guiding and supporting said upper plate, said plate engaging rollers and said disc engaging rollers having common axes.
 6. An ellipse compass as defined in claim 2 in which said base plate has an opening for access to one of said axis pin assemblies.
 7. An ellipse compass as defined in claim 1 in which said scriber member includes a pencil and pencil holder.
 8. An ellipse compass as defined in claim 1 in which said mounting members include a tongue portion on said upper plate with a slot therealong along which said scriber member is movable.
 9. An ellipse compass as defined in claim 1 in which setting indicating members are carried by said base plate for indicating the respective length settings of the major and minor ellipse axes. 